JPH01293261A - Brake gear with slip control - Google Patents

Abstract

PURPOSE: To perform the ABS control and TR control with a simple structure by connecting a brake tube from a master cylinder to one of a pair of control switching valves provided in each wheel cylinder, and connecting the other control switching valve to the brake tube through a relief tube, a preparatory chamber and a two-way driving pump. CONSTITUTION: Wheel cylinders VL, VR are provided with a pair of controllable switching valves EV1, EV2 and AV1, AV2, and a brake tube 12 from a master cylinder 3 is connected to one of the switching valves EV1, EV2. The other switching valves AV1, AV2 are connected to the brake tube 12 through a relief tube 14, a preparatory chamber 15 and a two-way driving pump P. The driving pump P is driven in the opposite direction by ABS control and TR control, and each switching valve EV1, EV2, AV1, AV2 is switched so as to control the brake hydraulic pressure to the wheel cylinders. The ABS control and TR control can be performed with a simple structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a brake device with slip control that includes a brake pressure generating device.

(Prior art, problems to be solved by the invention, and means for solving the problems) A braking pressure generating device of a braking device with slip control is as follows:
at least one brake cylinder that is unpressurized in a basic state, is connected to a reserve tank, and applies braking torque to driven wheels; and a first switching valve that connects the brake cylinder and the braking pressure generator; A brake pipe inserted therein, a relief pipe connected to the brake cylinder and having a second switching valve inserted therein, a first connection part and a second connection part, and one connection part is connected to the other connection part. A pressure medium pump is provided for delivering pressure medium to the brake pressure pump, the first connection being connected to the relief pipe and the second connection being connected to the brake pressure generator.

Such a braking device is described in German patent application No. 3431!
401. listed in the number. The brake pressure control method announced there allows the wheel to re-accelerate by discharging the pressure medium from the wheel brake of the wheel that is at risk of locking and returning it to the reserve tank, and the pressure medium is also returned to the reserve tank. Pressure medium is resupplied to the wheel brakes by pump means. Each of the pressure medium lines to the reserve tank and to the pump is provided with a check valve which, depending on the requirements of the control device, adjusts the corresponding pressure in order to adjust the optimum slip ratio. Open and close the media tube. The switching valve in the pipe leading to the pump can be considered an artificial valve, and the switching valve in the pipe leading to the reserve tank can be considered as an outlet valve.

Moreover, a control valve is connected to the pipe leading to the pump.

The control valve adjusts the pressure at the outlet of the pump to a value commensurate with the pedal force.

To control traction slip, the brake cylinders of the driven wheels are supplied with pressure medium to generate a braking torque opposite to the drive torque. In this way, the driven wheels are prevented from spinning when driving on slippery roads or when starting off. To prevent the drive torque from being overcorrected, the pressure medium from the wheel brakes can be drained. According to the aforementioned proposal, during traction slip control, pressure medium from the pump is supplied to the wheel brake, and no brake pressure generator is used in this operation. For this purpose, further valve means are provided, which prevent the pressure medium from the pump from flowing into the brake pressure generator connected to the reserve tank when not in operation.

In lieu of such a proposal, the aforementioned Patent Application Publication Section 34
No. 38401 also suggests supplying the pressure medium from the pump to the wheel brake via a relief pipe and not via a brake pressure generator. The switching valve of the relief pipe therefore performs the function of the inlet valve, while the switching valve of the pipe leading to the pump, ie the brake pressure generator, performs the function of the outlet valve. Indeed, such a braking device is the simplest. However, in spite of this, valve means are required for connection to the relief pipe, reserve tank or outlet of the pump.

The object of the invention is to provide a simpler braking device, preferably a braking device with slip control, which is able to fully perform the above-mentioned functions without the need for any additional valve means. .

The above-mentioned purpose is to enable the pump to have a discharge direction in both directions, such that pressure medium is delivered from the first connection to the second connection during brake slip control and from the second connection during traction slip control. This is achieved by delivering pressure medium to one connection.

The above-mentioned arrangement has particularly important advantages for the braking device described in German Patent Application No. MAE 01914. West German patent application publication box 3438401. Compared to the brake device of No. 1, the brake device of the present invention does not have an accumulator that is pressurized by a pump.

The pump is activated only when slip control is required. The pump delivers the pressure medium to the master cylinder with a center valve, which as a control valve forms the connection between the working chamber of the master cylinder and the reserve tank, controlling the pressure in the brake pipe in proportion to the pedal force. Adjust.

The pressure medium line from the working chamber of the master cylinder to the reserve tank must be shut off during traction slip control. This is brought about by two switching valve means inserted into the brake pipe.

According to this invention, the above-mentioned function can be performed without the need for a switching valve during traction slip control, and by reversing the delivery direction of the pump, the pump is directed to the relief pipe instead of the brake pipe. Deliver pressure medium. This can be done in a simple way by reversing the polarity of the supply voltage to the motor. Reversing the polarity of the power supply voltage to the motor can be accomplished in a low cost manner with simple electrical equipment. Even from a cost perspective,
The invention, which is most advantageous compared to the cost of additional valves, can be implemented in both closed and open circuits. In this connection, the closed circuit draws back the amount of pressure medium discharged from the wheel brake during brake slip control, so that this pressure medium is returned into the master cylinder. In an open circuit, there is additionally a connection between the relief pipe and the reserve tank via a check valve. During brake slip control, the pump therefore not only delivers the pressure medium discharged from the wheel brake, but also delivers additional pressure medium from the reserve tank.

In this way, it is possible to position the state of the master cylinder, ie, the piston of the master cylinder in a predetermined position during brake slip control.

(Examples) The present invention will be described with reference to Examples. The figure shows a schematic diagram of the braking device. The braking device is composed of a braking pressure generating device 1 consisting of a master cylinder 2 and a vacuum booster 3. The force for operating this device is provided by the pedal 4. The force from the pedal 4, increased with the aid of the vacuum booster 3, is transmitted to the bushing rod 5 of the master cylinder 2. Under the action of this force, the bushing rod 5 moves and the center valve 6 closes.

The pressure to be transmitted to the floating piston 9 is transferred to the action chamber 7.
occurs within. Under the action of this pressure, the floating piston 9 moves, the center valve 10 closes, and pressure is also generated within the working chamber 11. The working chamber 7.11 is connected to the brake pipe 8.12. For this embodiment, the brake pipe 12 is connected to the driven front wheels of the motor vehicle. Therefore, the brake pipe 12 is connected to the branch pipe 1
2-112'-, each connected to an individual wheel of the front axle. Each branch pipe 12', 12'' constituting the first switching valve has one of the inlet valves EVI, EV2 inserted therein, and the switching valves EVI, E
V2 is open when no current flows. The wheel brake communicates with a reserve chamber 15 via a relief pipe 14. Either one of the outlet valves AVI, AV2 as a second switching valve is inserted into the branch pipes 14'', 14'' of the relief pipe 14.
2 is closed when no current flows. The preliminary chamber 15 communicates with the reserve tank 13 through a check valve 16 that prevents flow toward the reserve tank 13 . Depending on the configuration of the braking device, a branch pipe leading to the reserve tank 13 may become unnecessary.

The pump P has a first connection part 17 and a second connection part 19. The first connection 17 is connected via a pipe 18 to the preliminary chamber 15.
is familiar with The second connection 19 leads to the brake pipe 12 via a pipe 20 .

Pump P is driven by motor M.

The motor M rotates in both directions. For this purpose, a change-over switch U is provided, which connects the voltage supply point of the motor M and the polarity of the input terminal source depending on the direction in which the motor M is rotated. The changeover switch U is part of an electronic circuit E, which receives a wheel slip signal S and transfers the switch signal V to the valves EV1 and E.
V2, AVI, A V 2 +,: Send.

The figure shows the brake device in the inoperative position.

The working chamber 7.11 communicates with the reserve tank 13 via a central valve 6.10. When the pedal 4 is depressed, pressure is applied to the working chamber 7.11 as described above. The pressure passes inside and reaches the wheels of the front axle via the brake pipe 12. Therefore, the pressure within the brake pipe 12, that is, within the wheel brake, is determined by the force applied to the pedal 4.

The rotational state of the braked wheels during braking is constantly monitored so that if there is a risk of locking of any wheel, it can be immediately detected.

In a certain situation, switch signal forces corresponding to this situation are supplied to the valves Ev1, EV2, AVI, AV2 and the changeover switch U. The first control means consist of closing the inlet valve Ev1 or EV2 of the wheel to be locked. Therefore, there is no possibility of further pressure being applied to the wheel brake connected to the closed artificial valve. In order to reduce the pressure, the outlet valve AVI or AV2 is opened, so that the pressure medium is discharged from the wheel brake into the fi chamber 15. At the same time, motor M is started, and depending on the rotation direction of motor M,
Pump P causes pressure medium to flow from connection 17 to connection 19 . The pump P extracts the pressure medium from the reserve type 15 and supplies the pressure medium to the brake pipe 12, and when the reserve chamber 15 is connected to the reserve tank 13, the pressure medium is also supplied from the reserve tank 13. .

As soon as the wheel to be locked is able to sufficiently re-accelerate, the outlet valve is closed and the inlet valve is opened. This allows new pressure medium to enter the wheel brake and builds up the pressure.

Slip control is performed by repeatedly increasing and decreasing brake pressure to keep the wheel slip rate constant.

This allows maximum braking force to be transmitted while maintaining the vehicle's maneuverability.

The explanation so far has been about brake slip control of the braking device. Traction slip control is implemented as follows.

In particular, when starting or when driving on a slippery road surface, the drive torque often exceeds the force that the wheels can transmit to the road surface. As a result, the wheels spin because the lateral force, which is a prerequisite for improving the running performance of the vehicle, cannot be transmitted. Therefore, a method has already been proposed in which excessive driving torque is corrected by the corresponding braking torque ga. When the above-mentioned condition is detected, the electronic circuit E sends a signal ■ to the inlet and outlet valves of the driven wheels. Therefore, the artificial valve EVI or EV2 valve is switched to the closed position and the outlet AV! Or AV2
switches to the open position. At the same time, motor M is started.

The motor M is activated in such a way that the pressure medium is delivered from the pump from the second connection 19 to the first connection 17 . The second connection part 19 connects the pipe 20 and the brake bamboo 1
2. It communicates with the reserve tank 13 via the action chamber 11 and the center valve 1o. The pressure medium delivered by the pump enters the relief pipe 14 via the first connection 17, the pipe 18 and the prechamber 15.

Even if the preliminary chamber 15 and reserve tank 13 are connected,
The check valve 16 prevents pressure medium from returning from the relief pipe 14 to the reserve tank 13 . Pressure medium can thus be supplied to the wheel brake via the outlet valve AVI or AV2.

The outlet valve AVl or AV2, which functioned as an outlet valve during brake slip control, now functions as a screamer valve. .

When the wheels are braked disproportionately, the pressure medium can be discharged via a check valve associated with the inlet valve EVI or EV2. Therefore, the check valve-equipped inlet valve EVI or EV2 functions as an artificial valve during brake slip control.

Reversing the action of known pressure regulating valves is made possible in a simple way by reversing the direction of supply by the pump. Therefore, it can be realized without increasing the number of valves at all.

[Brief explanation of the drawing]

The figure is a schematic representation of the braking device in the inactive position. ]... Braking pressure generator, 2... Master cylinder,
3... Vacuum booster, 4... Pedal, 5... Bush rod, 6.10... Center valve, 7.11
...Action chamber, 8.12.12', 12'', 18.20
...brake pipe, 9...floating piston,
13... Reserve tank, 14.14', 14-゛・
... Relief pipe, 15 ... Preparation chamber, 16 ... Check valve, 17 ... First connection part, 19 ... Second connection part,
21... External power supply, M... Motor, P... Pump, EVl, EV2... Inlet valve, Avl, AV2.
...Takehiko Suzue, Patent Attorney, Exit Valve Applicant Representative

Claims (5)

[Claims] (1) A braking pressure generating device that is unpressurized in its basic state and connected to a reserve tank; at least one brake cylinder that applies braking torque to driven wheels; a brake cylinder and a braking pressure generating device; a brake pipe with a first switching valve inserted therein, a relief pipe connected to the brake cylinder with a second switching valve inserted therein, and the first connection part and the second connection part. the pressure medium is delivered from one connection to the other, the first connection being connected to the relief pipe and the second connection being connected to the braking pressure generator. In brake systems with slip control with a pressure medium pump, the delivery direction of the pressure medium pump is possible in both directions, and during brake slip control the pressure medium pump transfers pressure from the first connection to the second connection. During the delivery of the medium and traction slip control, the pressure medium pump
Braking device with slip control, characterized in that the pressure medium is delivered from the second connection to the first connection. (2) The relief pipe and the first connection part of the pump are connected to the reserve chamber, and the reserve chamber is connected to the reserve tank via a check valve, and the check valve is connected to the reserve tank. 2. The braking device with slip control according to claim 1, wherein the braking device prevents a flow toward. (3) The braking device with slip control according to claim 1 or 2, wherein the pressure medium pump is driven by a motor, and the polarity of the voltage supply point of the motor can be switched by a changeover switch means. (4) In the basic state, the first switching valve maintains the brake pipe in an open state, while the second switching valve closes the relief pipe. Braking device with slip control described in . (5) The braking device with slip control according to any one of claims 1 to 4, wherein the pressure medium pump is activated only during slip control or traction slip control.